a little bird told me (something)
used to say that you know something, but you will not say how you found out

[TahlilGaran] Dictionary of Contemporary English ▲

a little bird told me.
A little bird told me (so).
something that you say in order to let someone know that you are not going to tell them who gave you the information being discussed.
'So who told you she'd got the job?' 'Oh, let's just say a little bird told me so.'

[TahlilGaran] English Idioms Dictionary ▲

a little bird told me
something is learned from a mysterious and secret source who you do not want to name
A little bird told me that I would be getting a nice present from my boyfriend next week.

A little bird told me that my friends will have a surprise party for me next week.

[TahlilGaran] English Idioms Dictionary ▲

a little bird told me
To have learned something from a mysterious, unknown, or secret source.
"Who told you that Dean Smith was resigning?" Peter asked. "A little bird told me," Jim answered.

[TahlilGaran] English Idioms Dictionary ▲